Diplomats from some developing countries may "occupy" the UN climate negotiations that begin on Monday in Durban by staging sit-ins and boycotts over the lack of urgency in the talks.

A Filipino activist during a climate change rally near the US embassy in the Philippine capital, Manila, a week before the talks in Durban. (Photograph: Aaron Favila/AP) The move follows a call by the former president of Costa Rica for vulnerable countries to refuse to leave the talks until "substantial" progress has been made.

"I have called on all vulnerable countries to 'occupy' Durban. We need an expression of solidarity by the delegations of those countries that are most affected by climate change, who go from one meeting to the next without getting responses on the issues that need to be dealt with," said José María Figueres.

"We went to Copenhagen [in 2009] with the illusion we could reach an equitable agreement. We went to Cancún [in 2009] where we saw slight but not sufficient progress. Frustration is now deep and building. Now we hear that we will need more conferences. Sometime we have to get serious. We should be going to Durban with the firm conviction that we do not come back until we have made substantial advances."

Spokespeople for developing country negotiating blocs declined to comment on the call for a revolt, but one ambassador said from Durban: "The Occupy Wall Street movement and the Occupy the Climate Change negotiations movement confront the same problem. We need this if we want to have any positive result. Otherwise it will be worse than Cancún."

But he warned: "In the corridors [here] there is talk of occupying the meeting rooms, but there could be sanctions. So it needs to be big inside in order to have impact and nobody is punished. We are at the beginning."

Seyni Nafo, spokesman for the important 53-country Africa group said: "We understand the [financial] situation in Europe and Japan but it seems climate change is now not on the global agenda. Action that might make it visible must be considered. We are exploring a lot of avenues and options. You have to take that seriously."

Frustrations mounted last month when, after months of tense negotiations, developing countries appeared to have succeeded in their demand for access to a multi-billion dollar Green Fund to help them adapt to climate change. But at the last minute the US and Saudi Arabia withdrew their support.

Resentment was further stoked this week when the Guardian revealed that rich countries had decided to shelve plans for a global agreement on climate change within the next few years, instead pushing for an agreement by the end of 2015 or 2016, and not coming into effect until 2020 despite scientists saying that this risked catastrophic climate change.

A possible postponement of a deal was condemned on Tuesday by the UN environment chief, Achim Steiner, who said it would be a "political choice" rather than one based on science.

Jorge Argüello, chair of the powerful G77 and China coalition of 131 countries, said: "[We] trust to see in Durban a fair and equal treatment of all issues that are important to all parties. A serious imbalance in the progress of issues can clearly not be conducive to a successful, comprehensive and balanced outcome."

"The climate change process is too crucial to the survival of humanity and the dignity of each of us, it is sad to see some parties using it just as a toy in a promotional agenda. The African leaders have expressed in different fora that Durban can not become the grave of the Kyoto Protocol, and we are completely supportive of that ambition."

Sheik Hasina, the prime minister of Bangladesh, said: "Climate change caused over 300,000 additional deaths last year. We the vulnerable countries suffer the most for our limited coping capacities. Bangladesh and other vulnerable countries cannot wait for international response to climate causes ... we are implementing 134 climate change adaptation and mitigation action plans."

Radical action at climate talks has produced results in the past. African nations boycotted the climate talks in Barcelona in 2009 for a day, and won themselves a promise from rich countries to make more efforts to deepen 2020 cuts in greenhouse gas emissions.

The Alliance of Small Island States, which represents some of the countries most at risk from global warming, called any moves to delay a new treaty "reckless and irresponsible".